The primary goal of this application is to promote interdisciplinary research on typical and atypical development, using biological and behavioral tools and techniques, by training highly qualified postdoctoral fellows. We shall target trainees who have received Ph.D.s either in behavioral disciplines, such as Psychology or Communicative Disorders, or in biological disciplines, such as Neuroscience, along with M.D.s from Pediatric disciplines such as Developmental Pediatrics or Child Psychiatry. We propose to train three Ph.D. and two M.D. postdoctoral trainees per year, in three-year traineeship cycles, using an innovative program that provides a rich combination of didactic and intensive research experiences. More specifically, the training program will have four key elements: (a) mechanisms for coordinating and monitoring individualized training;(b) intensive research training experiences;(c) a core curriculum;and (d) a requirement that training experiences result in well-defined products in a timely manner. The intensive research experiences will be designed to achieve the following goals: (a) increase the trainee's knowledge of typical and atypical development;(b) expand the trainee's repertoire of techniques for designing and conducting biological or behavioral research;and (c) enable the trainee to develop a programmatic line of interdisciplinary inquiry. The public health relevance will be the development of a cadre of medical and biobehavioral scientists who possess the requisite skills and knowledge to integrate the study of typical and atypical development.